Trihybrid nanofluid exhibits significantly higher thermal conductivity compared to individual nanoparticles. This enhanced thermal conductivity is especially notable at low concentrations, leading to improved heat transfer efficiency. Hence, trihybrid nanofluids have potential practical applications in various heat transfer systems, cooling, and heating processes. This study investigates the entropy-based thermal aspects of MHD trihybrid nanofluid composed of MgO, TiO2, and CoFe2O4 nanoparticles in combination with water as the base fluid. The analysis is conducted between two parallel plates that are subjected to squeezing motion. Novel aspects encompassing thermal radiation, viscous dissipation, reaction, and temperature-dependent viscosity are taken into consideration. The governing PDEs are transformed into a system of ODEs using appropriate similarity transformations. The numerical solution is achieved through the implementation of the RKF method with a shooting technique. The effects of emerging parameters on velocity, temperature, concentration profiles, and engineering quantities are investigated and discussed through graphs and tables. The outcomes indicate that suction and magnetic fields cause a 7.50% decrease in nanofluid velocity due to augmented squeezing and medium factors. The temperature increases by 8% in trihybrid nanofluids with stronger radiation. An increase in the reaction leads to a decrease in the concentration of CoFe2O4/H2O nanofluid by 5.53%. An escalation in the Brinkman number results in simultaneous increments of 6.04% in entropy and 4.83% in the Bejan number. Magnetic field strength reduces friction by 2.46% on both plates. Enhancing the radiation parameter leads to a 7.31% rise in heat transfer at the lower plate, but it declines by 4.49% at the upper plate. Higher concentration ratios lead to 5% higher Sherwood numbers on both plates.